Another FrankenBurner

3D printed plastic burner experiments (photo heavy)

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The first image of the small flame is below 1 psi.  The aerospike really moves the air.

I tried to create a semi match of the reducer shape in the spike.  

 aerospike.jpg.faf94e1674318ee681acd8ac1248373e.jpg

Now I want to play with lengthening the ribs a little bit as they were so short the first time around.  See if it hurts or helps.

I have also modelled what I thought Frosty might have been saying.  A thin disc with a smaller spike.

2477268_spike2.jpg.277c8e7a93dc7598037681232b673493.jpg

 

I look forward to seeing what a high rotation flame will do when the burner is put into a forge.

When you say fins in the nozzle, are you thinking straight fins or something opposing the flame rotation?

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I was a bad scientist and I changed more then one thing at a time.  I will go back and print each thing in it's turn but I had an idea and went with it. 

I have enough versions now that the version system I came up with is no longer entertaining so I counted the versions and will be adding them linearly from now on.  

Here is the new golden boy:

v30.jpg.29c0f45da17d749d981c41c12f2bc482.jpg

He is version 2.7.11 with some changes:

  • The ribs have been lengthened to 1/2 inch (from less then 3/8)
  • The airfoil has been changed to a laminar profile
  • The inlet to rib ratio has been bumped to 60/40 (from 50/50)

This burner induces the most air of the bunch.  The flame has visible rotation like 2.7.11 but without the instability I was seeing.  

Now I am printing versions with one change at a time, like I should have, to see what each change brings.  V31 is the same but the inlet to rib ratio is back to 50/50.  I also intend on removing the small radius at the top of the reducer to see what a sharp edge does there.

 

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On 2/18/2019 at 8:51 PM, Another FrankenBurner said:

I have also modelled what I thought Frosty might have been saying.  A thin disc with a smaller spike.

 

That's as close as can be expected from a text description by someone skyballing. Yes on the cap. The aerospike I was visualizing would maybe be longer but that depends on how far into the intake the jet is set.

I found a copy of UGHHH, Draft sight 2D on my comp and am trying to see if I can get the free version reactivated. 

Fingers crossed.

Frosty The Lucky.

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The jet position is flexible.  I have positioned it directly in the throat and all the way back at the mount block.  Between 1/4" behind the throat and 1/4" behind the end of the reducer, it is hard to discern much difference in induction.  I usually position it around where the ribs and the reducer meet.  

I just noticed the aerospike versions induction curves are much better than the rest.

 

 

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I have printed and tested v31 and v32.  

v32.jpg.3cd6f4fd50b1adc00a555564728ed8c7.jpg

V31 induces more air and has better mixing then v30.  V32 did not perform as well.  It produces a large secondary flame.

The changes in the flame are all small lately.  I have to pay extra attention to see them.  I played with jet position while paying closer attention and have found that a 1/4" back from the throat is the best position in several version.  This is much deeper into the reducer then I had been positioning it usually.

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v34.jpg.7e7490847c8e07a06ad089c4148f8118.jpg

Similar to v30 but the top of the reducer has no radius and the ribs are now rotated a bit more.  This extra rotation has added to the flame stability and air induction.  Previous versions which could support the 030 mig tip were at the low border of neutral flame.  This guy accomplishes a good neutral flame at 2 - 15 psi with the 1.25 inch nozzle.  

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48 minutes ago, Another FrankenBurner said:

This guy accomplishes a good neutral flame at 2 - 15 psi with the 1.25 inch nozzle.  

A 1 1/4" nozzle! It must go through 40 lb. of propane in about 30 seconds! :o

The plan view of V30 shows fins inside out to what I was visualizing. The inside surface following the radius of the burner inlet at that radius and the airfoil "upper" face on the outside with the leading edge into the wind. 

I've forgotten to practice but 2 D cadd is still stupid complicated with bells and whistle laden menus for every darned thing. I REALLY miss the old stuff but it's not supported on mmodern comps. Sigh.

Enough whining for now, more after I try it again.

Frosty The Lucky.

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The 3/4 inch modified sidearm burner in my refrigerant jug forge has an 035 tip running at 5 psi and it runs for a long time on a 5 gallon tank.  It runs quite rich and is too big so I have nice blue dragons breath.  V34 uses an 030 tip and the same size nozzle with a smaller slower neutral flame.  I am hoping for fuel savings.  

As to the profile, a picture would be great.  Hand drawn is fine as well.  I had a few curved airfoils to match the radius but they all had turbulence in the lower curve.  I don't know much about airfoils so I most likely did them wrong.  Also, because the air induces in straight lines from all directions until it enters the inducer, not all of the air goes across the airfoil in the direction it would if it were a wing.  Having the vortex inside helps the streams flow across the foils like I originally thought.  I think your idea is good one.  Having the upper surface at a higher velocity and a lower pressure seems like it would be more likely to track the air across the upper of the airfoil to the outside of the vortex and the lower side of the next rib.  

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You're absolutely right, incoming air can't have a lateral direction untill it enters the existing vortex in the burner. Nevermind. 

Good greif that's just too basic to forget. Guess I'll redirect my mind's eye now.

Frosty The Lucky.

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At this point I am changing the angle of ribs in relation to the jet to see what does best.  My initial suspicions are that close to 90° starts to defeat the point in airfoil at all, close to 0° is a paddle which gets in the way vorticial flow.  Version 34 happened to be at 75°.  

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I'm not clear on the angle you're referring to. :huh:

Frosty The Lucky.

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Ayup, that's all I could think of logically but didn't want to assume. Were it a jet wing it'd be the sweep IIRC from reading about wings maybe 40 years ago.  I remember the dihedral clearly, sweep not so clear but it's the first term to come to mind.

Anyway, yes there is a limit to how much sweep is beneficial and much past the point of limited returns performance really falls off.

Frosty The Lucky.

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The most important figure for me is a stable flame at 2 PSI; that tells me you are solidly on track, to maintain that low a figure in a 3/4" burner size, and still maintain a single flame envelope. You are having your cake and eating it too. This is as good as anything I've seen with ribbon burners, and that is going pretty far :D

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55 minutes ago, Mikey98118 said:

You are having your cake and eating it too.

Uh Mike: Did you know that's how the Unibomber wrote the saying in his manifesto? Most folk can't eat their cake and have it to. That's the only way I'd heard it till the Unibomber came on the scene and they decided to publish his manifesto and hope for leads. Of course I live in the woods. 

I'm really liking this line of burners too, a little finesse using one and, "you can bake your cake and eat it too." :)

Frosty The Lucky.

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Frosty, 

It turns out that this was actually the original form of the proverb, which dates to the 16th century.  This is how it was said and taught until around 1935 when popular usage of the phrase changed (according to Google).  I believe that the reason Ted Kaczynski used that phrase is because a professor of his in University said it like that and he used the phrase in that way (I could be wrong on that part).

Lou 

 

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I'm glad someone else likes these burners too.  My wife can only look at so many plastic burners, which look the same, before even the pretend enthusiasm runs low.  

I think they are getting close now.  Most of my recent experiments decreased performance.  I still have a few more things to try, then the next step will be a bit more effort towards the casting side.  

 

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20 hours ago, louspinuso said:

Frosty, 

It turns out that this was actually the original form of the proverb, which dates to the 16th century.  This is how it was said and taught until around 1935 when popular usage of the phrase changed (according to Google).  I believe that the reason Ted Kaczynski used that phrase is because a professor of his in University said it like that and he used the phrase in that way (I could be wrong on that part).

Lou 

 

That makes sense Ted was the type to use archaic terminology to demonstrate his disdain for modern society. Brilliant guy but damaged goods. His brother recognized his writing style and turned him in to the FBI. It's a sad tale all round.

19 hours ago, Another FrankenBurner said:

I'm glad someone else likes these burners too.  My wife can only look at so many plastic burners, which look the same, before even the pretend enthusiasm runs low.  

Maybe start using different colors? Once you decide on the best burner the others might make marketable Christmas tree ornaments. 

Frosty The Lucky.

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I have printed several versions with the ribs at different angles.  V38 is now the golden boy at an angle of 80°.  I printed 60°, 70°, 75°, 80°, and 90°.  V38 is capable of 1-15 psi with the big nozzle and the 030 jet.  If I slide the nozzle back a bit, it runs on the peg at a very low output.  I am excited about this one.  The next one(v40) will be v38 with 5/8" long ribs instead of 1/2".

Here is the gauge on the minimum peg with the 030 and much less nozzle overhang:

IMG-0393.JPG.592e1cc6c8409f3331ca32019b21341e.JPG

Here is 1 psi with normal overhang:

IMG-0406.thumb.JPG.177bad6d252bdd314342897a4163cff5.JPG

Here is 5 psi:

IMG-0402.JPG.ebb515578aa2d33e99a5874060c347a0.JPG

Here is 15 psi:

IMG-0411.thumb.JPG.2a98b436b33f4edf6c1c3007a5ba573a.JPG

2 hours ago, Frosty said:

Maybe start using different colors? Once you decide on the best burner the others might make marketable Christmas tree ornaments. 

I should do something.  The burner tub is getting deep.

IMG-0412.thumb.JPG.8b831d8d9916a2b407da70f595e7209c.JPG

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You call THAT a bucket?:rolleyes: I buy larger to go ice creams at the local drive through. There you go, hot fudge and sprinkles will get the missus attention again.

Frosty The Lucky.

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11 hours ago, Another FrankenBurner said:

I have printed several versions with the ribs at different angles.  V38 is now the golden boy at an angle of 80°.  I printed 60°, 70°, 75°, 80°, and 90°.  V38 is capable of 1-15 psi with the big nozzle and the 030 jet.  If I slide the nozzle back a bit, it runs on the peg at a very low output.  I am excited about this one.  The next one(v40) will be v38 with 5/8" long ribs instead of 1/2".

Do you have these STL's available?  I'm still a ways away from doing a diy burner build, but this looks like a great way to improve efficiency when I get to that point.

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I have not made the STL files available yet.  I am waiting until I am satisfied with the design.  I would also like to get the cast process down, get some in metal, and crash test them in a few forges.  I need to test them with the back pressure and I want to make sure they don't Chernobyl.

Unfortunately, for the home brew, this burner head would require 3d printing and aluminum casting.  

11 hours ago, Mikey98118 said:

One thing your experiments have proved beyond doubt is that fuel/air mixing is of primary importance.

Agreed.  If a burner can not induce the correct volume of air for the volume of fuel and mix them properly, it is wasting fuel.  My original intention was to learn about burners so I could build some that lower my fuel costs.  I have learned quite a bit and continue with each version.   What I thought was happening and what I should be striving for has changed a few times through the process.  It's been fun.  I am glad my experiments are useful.

 

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49 minutes ago, Another FrankenBurner said:

I have not made the STL files available yet.  I am waiting until I am satisfied with the design.  I would also like to get the cast process down, get some in metal, and crash test them in a few forges.  I need to test them with the back pressure and I want to make sure they don't Chernobyl.

Understood.  TBH, even if you don't release the STL, I'm sure people would pay to get some based on the results I'm reading here.

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Well, there is going to be lots of interest in the data from other casters with print technology; that is great.

But, someone is going to build these parts in aluminum too; it's just a given. These air chambers would make the ultimate kit part; I would buy one myself!

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